The ability to independently tailor the properties of three-dimensional hydrogel-based systems is useful for a variety of applications including, but not limited to, biomedical applications (for example, the development of drug delivery systems, tissue engineering constructs, and biosensors). In addition, such systems permit the determination of the effects of cell-cell and cell-material interactions which could potentially provide a means of guiding cellular behavior. Although, the ability to create internally complex three-dimensional materials on rigid substrates has been investigated, the ability to do the same within preformed hydrogels has only recently been examined. For example, West and co-workers have demonstrated that uniform and freeform 3D patterns could be created within preformed poly(ethylene glycol)-diacrylate (PEGDA) hydrogels via single-photon absorption (SPA) and two-photon absorption (TPA) photolithography. Unfortunately, radical polymerization of diacrylated and/or dimethyacrylated PEG results in heterogeneous crosslinked networks making it difficult to accurately predict and manipulate the physical and mechanical properties of the material.
Accordingly, there is a need for methods for producing hydrogels with relative control of the physical and chemical properties of the material.